We anchored overnight there a few years ago. I have never seen that bay busy. There is a lot of coral on the bottom, so you need to arrive early enough to find large patch of sand.
I don’t believe that there are any mooring balls other than national park day use balls.
Warren S/V Scuba Doo Lagoon 50 (winner of best crewed yacht under 55 feet at the St. Thomas crewed yacht boat show).